The referenced U.S. application Ser. No. 149,365--which corresponds to published German patent disclosure document DE-OS No. 29 25 187--describes a nozzle which has a movable valve needle and, upon lifting off of the valve needle from a valve seat, interrupts an electrical circuit. The valve needle is electrically insulated from the remainder of the injection nozzle structure, except at the valve seat, so that lifting-off of the needle from the seat opens an electrical switch. The needle is lifted off the valve seat by hydraulic pressure. When the needle has reached its terminal lifted or raised position, it engages an abutment formed in the valve housing, so that the needle again makes electrical contact with the valve housing. This second connection, then, provides a second "closed" output signal which is superimposed over that of the first "open" or interrupting signal. Separating the two signals, which follow each other in rapid sequence, is difficult and requires additional electrical components. It has been proposed to provide an insulating bushing on the abutment in the housing against which the movable valve needle impinges. No suitable insulating material, however, has been found since coatings which are capable of accepting the impacts by the moving needle rapidly wear out and become non-insulating or other coatings, capable of accepting the forces, become deformed, so that the length of the stroke of the needle changes with change in the relative position of the abutment surface and the moving valve needle.